Lysiloma

Taxonomy

Lysiloma G. Bentham London J. Bot. 3: 82. Jul 1844.

Subfamily: Mimosoideae.
Phylogenetic Number: 2.5.06.
Tribe: Ingeae.
Species Studied - Species in Genus: 14 studied; 8 in genus.

Description

Fruit: A legume; unilocular; 10–25 cm long; 1–5.5 cm wide; 0.02–0.5 cm thick; 2–9 times longer than wide, or more than 9 times longer than wide; with deciduous androecial sheath; with deciduous corolla; with deciduous calyx; without orifice formed by curving of fruit or fruit segments; straight (or nearly so); not plicate; twisted (basally), or not twisted; symmetrical; linear to oblong; not inflated; flattened; without beak; rounded at apex to tapered at apex; aligned with longitudinal axis of fruit; short tapered at base to tapered at base, or rounded at base; aligned with longitudinal axis of fruit; with the apex and base uniform in texture; coriaceous to membranous; seed chambers externally visible; margin not constricted; margin without sulcus; margin plain; wing(s) absent; stipitate, or substipitate; with the stipe up to 40 mm long; tardily with all layers dehiscing, or indehiscent; splitting along suture(s). Dehiscence of valves active; with valves breaking (from replum thus opening though not falling away). Replum visible, or invisible. Epicarp glossy to dull; monochrome; brown (to blackish brown), or black; with surface texture uniform; glabrous to pubescent and indurate; with hairs erect; with simple hairs; eglandular; without spines; not smooth; with elevated features; not veined, or veined (parallel, extending across valve or to center of valve); transversely veined relative to fruit length; not tuberculate; checking and exfoliating; without cracks; without embedded tissue, much thicker than epicarp, running from base to apex. Mesocarp present; surface not veined; 1-layered; without balsamic vesicles; without reniform canals; solid; coriaceous. Endocarp present; visible; dull; opaque; monochrome, or mottled; tan; with mottling more or less uniform and over seed chambers; with purple overlay and tan overlay (darker, over seed chambers); smooth; without adhering pieces of testa; septate; not exfoliating; remaining fused to mesocarp and epicarp, or separating from mesocarp; entire, or separating into 1-seeded winged segments. Seed(s) 2–16; length transverse to fruit length; neither overlapping nor touching; in 1 series. Funiculus 2.5–20.5 mm long; of 1 length only; filiform; hooked. Aril absent.

Seed: 5.3–10 mm long; 3.8–6.5 mm wide; 1–2 mm thick; not overgrown; not angular; symmetrical; oblong to ovate; compressed to flattened; with surface smooth; without visible radicle and cotyledon lobes; without hilar sinus; without umbo on seed faces; without medial ridge on each face. Cuticle not exfoliating; not inflated; not wrinkled. Testa present; without pieces of adhering epicarp; not adhering to endocarp; free from endocarp; glossy; not modified by a bloom; colored; monochrome; brown; glabrous; not smooth; with recessed features; concaved; osseous to coriaceous. Pleurogram present; 75 %. Pseudopleurogram absent. Fracture lines absent. Rim absent. Wing(s) absent. Raphe not visible. Hilum present; visible, or fully concealed; concealed by funicular remnant; without faboid split; punctiform; subapical to radicle tip to apical at apex of radicle tip; flush; not within corona, halo, or rim. Lens discernible; 0.1 mm long; with margins straight; linear; not in groove of raphe; mounded (within hilar depression); dissimilar color from testa; white; not within corona, halo, or rim. Endosperm present, or absent; thin; not pluglike and not resembling tip of radicle; adnate to testa. Cotyledons smooth; both outer faces flat; both the same thickness; both more or less of equal length; not folded; margin entire 180 degrees from base of radicle; similar at apex; partially concealing radicle; with lobes; with lobes overlapping; with basal groin formed by lobes; with the interface division terminating at base of radicle; without margins recessed; inner face flat; glabrous on inner face. Embryonic axis straight; parallel to length of seed; without a joint evident between the radicle and the cotyledons. Radicle differentiated from cotyledon; straight with embryonic axis; centered between cotyledons. Plumule well developed; glabrous.

Distribution

Mexico, The Greater Antilles, and southern Florida and Arizona.

New World; Mexico, West Indies, Central America, and United States (the Greater Antilles and southern Florida and Arizona).

Generic Notes

Lysiloma fruits are unusual because the entire valves break from the replum, thus opening though not falling apart. Barneby and Grimes (1996) reviewed the genus restricting its distribution to Mexico, the Greater Antilles, and southern Florida and Arizona and its numberr of species to eight which are used here.